It is said to feature a powerful quad-core Snapdragon 800 processor, as well as 2GB of RAM, 64GB of internal storage and a 3200 mAh battery.

The One Max would be designed to take on Samsung's own rumoured 6-inch device, the Galaxy Note 3. While little is known about the upcoming Samsung phone, its name has just received certification in Indonesia, suggesting it is on the way.

The last time HTC attempted a similar-sized device was with the 7-inch Flyer back in 2011, which featured clever handwriting input. Since then both Samsung and Sony have implemented similar systems. This could mean stylus support will ship with the One Max.

Also rumoured to be due for release this year from HTC is the One Mini, a smaller mid-range device with the same design as the larger HTC One but with a cheaper price tag.